Frequency-dependent polarization of incoherently excited fluorescence

We use detailed-balance considerations to relate the frequency-dependent polarization of atomic fluorescence excited by broad-band radiation to the polarization properties of the collision-induced fluorescence line excited by narrow-band radiation. The polarization of the fluorescence in the first case must display a change when the detected frequency is tuned outside the bandwidth, due to the contribution of Rayleigh scattering. In the special case of adiabatic reorientation followed by emission in the quasistatic wing of the spectral line, we derive explicit expressions for the frequency-dependent polarization in terms of the contributions to the quasistatic profile from the various interatomic difference potentials.